In general, a continuous fastener element having a coil shape or a zigzag shape and used in a slide fastener is manufactured in a manner such that a thermoplastic synthetic resinous material is extruded to mold linear monofilament, the obtained monofilament is molded in a coil shape or a zigzag shape, and a part of the monofilament is pressed at a constant interval to mold a coupling head.
Further, for example, Japanese Patent Application Publication No. 7-63411 (Patent Document 1) or the specification of Japanese Patent No. 3698562 (Patent Document 2) discloses a method or a device for manufacturing a coil-shaped continuous fastener element by molding synthetic resinous monofilament.
The device disclosed in Patent Document 1 includes a supply roller which normally supplies a constant amount of synthetic resinous monofilament, a stamp-molding portion which has a pair of molding rollers stamp-molding a coupling head or the like on the monofilament supplied from the supply roller, and a coil-shaped element molding portion including mandrel which molds the stamp-molded monofilament into a coil-shaped continuous fastener element.
The supply roller in Patent Document 1 includes a supply pulley around which the monofilament is wound a number of times and supplies the monofilament to the stamp-molding portion, so that a constant amount of the monofilament may be normally supplied to the stamp-molding portion by the supply pulley.
For example, as shown in FIG. 8, a stamp-molding portion 50 includes a circular roller 51 and an annular roller 52 serving as the pair of molding rollers, and a recess-like tooth 54 is provided on an outer peripheral surface 53 of the circular roller 51 at a constant interval. Further, a protrusion-like tooth 56 is provided on an inner peripheral surface 55 of the annular roller 52 at a constant interval to correspond the position of the recess-like tooth 54 of the circular roller 51, whereby the stamp-molding process may be performed along with the circular roller 51. Furthermore, the circular roller 51 and the annular roller 52 are configured to revolve around a mandrel to be described later of the coil-shaped element molding portion while they rotate.
In the stamp-molding portion 50, the circular roller 51 and the annular roller 52 are rotated, and monofilament 57 supplied from the supply roller is guided to a gap between the outer peripheral surface 53 of the circular roller 51 and the inner peripheral surface 55 of the annular roller 52. Accordingly, the monofilament 57 is press-molded by the protrusion-like tooth 56 of the annular roller 52 and the recess-like tooth 54 of the circular roller 51, so that a coupling head or the like having a predetermined shape is formed on the monofilament 57.
The coil-shaped element molding portion includes a rod-like mandrel which is fixed to a mandrel holder, and the circular roller 51 and the annular roller 52 revolve around the mandrel while they rotate to wind the monofilament 57 having the coupling head molded thereon around the mandrel, so that the monofilament 57 is molded in a coil shape. Furthermore, a passage is provided in the mandrel in the longitudinal direction to allow a core thread to pass through.
Therefore, the monofilament 57 having the coupling head molded by the circular roller 51 and the annular roller 52 of the stamp-molding portion 50 is guided to the mandrel of the coil-shaped element molding portion, and the circular roller 51 and the annular roller 52 revolve around the mandrel, so that the monofilament 57 is wound around the mandrel to be molded in a coil shape. Also, the core thread is discharged from the front end of the mandrel through the passage provided inside the mandrel, so that the coil-shaped continuous fastener element having the core thread inserted therethrough is manufactured.
On the other hand, the device disclosed in Patent Document 2 includes a monofilament supply portion which supplies monofilament, a winding portion which has a mandrel and winds the monofilament around the mandrel to have a coil shape, and an element molding portion which molds a coupling head or the like to have a predetermined shape on the monofilament wound around the mandrel.
The monofilament supply portion includes a large spool around which the monofilament is wound, a flier which guides the monofilament unwound from the spool, and a guide roller which switches the carriage direction of the monofilament.
The winding portion includes a rotary body which has a monofilament guide hole, a rod-like mandrel, a core thread bobbin which supplies a core thread, and a core thread drawing body which draws out the core thread from the core thread bobbin. Further, a core thread guide groove is formed in the mandrel throughout the entire length thereof to guide the core thread in a sliding manner.
In the winding portion, the monofilament supplied from the monofilament supply portion is guided to the mandrel through the monofilament guide hole of the rotary body by rotating the rotary body, so that the monofilament is wound around the mandrel to mold the monofilament in a coil shape.
The element molding portion includes a pair of screws which is disposed with the mandrel of the winding portion interposed therebetween, upper and lower coupling head forming portions which are disposed with the mandrel interposed therebetween and form a coupling head on the monofilament molded in a coil shape, and an upper leg forming portion which bends a part of the monofilament formed as a continuous fastener element upper leg portion in a step shape.
Accordingly, the monofilament wound around the mandrel is carried forward in a coil shape with the rotation of the left and right screws. In accordance with the carriage, the coil-shaped monofilament first reaches the coupling head forming portion, and the coupling head forming portion press-molds the monofilament at a predetermined interval, so that a coupling head is formed on the monofilament.
Subsequently, the monofilament having the coupling head formed thereon is carried to the upper leg forming portion with the rotation of the left and right screws, and the monofilament is punched at a predetermined interval by the upper leg forming portion, so that a step portion is formed on a portion formed as the fastener element upper leg portion. Subsequently, the core thread discharged from the front end of the mandrel is inserted into the coil-shaped monofilament, so that a coil-shaped continuous fastener element is manufactured which has a step portion accommodating a sewing thread in the upper leg portion.
Incidentally, in the slide fastener having the coil-shaped continuous fastener element, a lubricating material is applied to the outer peripheral surface of the continuous fastener element in order to smoothly slide the slider along the element row or smoothly engage the left and right element rows with each other.
Further, Japanese Patent Application Publication No. 1-19888 (Patent Document 3) discloses a configuration in which minute grooves or recesses are formed on the entire outer peripheral surface (the surface) of the continuous fastener element when a lubricating material is applied to the outer peripheral surface of the continuous fastener element. Furthermore, Patent Document 3 discloses an example of a method of forming minute grooves or recesses on the outer peripheral surface of the continuous fastener element in a manner such that minute uneven portions are formed on an opening of a nozzle extruding monofilament, the surface of the monofilament is rubbed by an abrasive member with minute particles, or a sand blasting process of blasting minute particles is performed.
In this manner, when minute grooves or recesses are formed on the outer peripheral surface of the continuous fastener element, the lubricating material applied to the continuous fastener element may be buried in the grooves or recesses, so that the lubricating material may be properly attached to the continuous fastener element.
For this reason, for example, when the slide fastener having the continuous fastener element is cleaned, it is possible to prevent the lubricating material from being separated from the continuous fastener element even when an external force is exerted on the lubricating material applied to the continuous fastener element during the cleaning or the like or an external force is exerted on the lubricating material due to the contact between the coupling heads of the left and right continuous fastener elements or the contact between the continuous fastener element and the slider when the slide fastener is opened or closed. Therefore, even when the slide fastener is repeatedly cleaned or the slider is repeatedly opened or closed, it is possible to sustain the effect of the lubricating material and smoothly perform the sliding action of the slider or the engaging action of the element rows for a long period of time.
On the other hand, Japanese Patent Application Laid-Open No. 2005-160667 (Patent Document 4) discloses a configuration in which a plurality of independent fastener elements are fixed to a fastener tape by injection-molding even the fastener tape using, for example, a synthetic resin, wherein minute uneven portions are formed on the outer surface of each of the independent fastener elements, so that the outer peripheral surface is finished into a pearskin of which a ten-point average roughness is from 0.8 to 200 μm.
In Patent Document 4, the method of forming the uneven portions on the outer surfaces of the independent fastener elements is not particularly limited. However, for example, a method is disclosed in which uneven portions are formed on a cavity surface of a mold used for injection-molding to form minute uneven portions on the outer surfaces of the independent fastener elements.
Then, according to Patent Document 4, since the outer surface of the independent fastener element is finished into the pearskin, light is irregularly reflected from the pearskin surface. For this reason, the slide fastener having the fastener element is dyed in the same bath to decrease a difference in the brightness between the fastener element and the fastener tape, so that the fastener element and the fastener tape have the same color tone.
Furthermore, in Patent Document 4, the shape of the slide fastener is not particularly limited, and there is a description that a coil-shaped continuous fastener element molded from monofilament may be used as the fastener element in addition to the independent fastener element formed by the above-described injection molding.
Patent Document 1: Japanese Patent Application Publication No. 7-63411
Patent Document 2: Specification of Patent No. 3698562
Patent Document 3: Japanese Patent Application Publication No. 1-19888
Patent Document 4: Japanese Patent Application Laid-Open No. 2005-160667